diff --git a/mailcow/src/mailcow-dockerized/data/Dockerfiles/unbound/Dockerfile b/mailcow/src/mailcow-dockerized/data/Dockerfiles/unbound/Dockerfile
index d9756d0..b190908 100644
--- a/mailcow/src/mailcow-dockerized/data/Dockerfiles/unbound/Dockerfile
+++ b/mailcow/src/mailcow-dockerized/data/Dockerfiles/unbound/Dockerfile
@@ -1,6 +1,6 @@
 FROM alpine:3.17
 
-LABEL maintainer "Andre Peters <andre.peters@servercow.de>"
+LABEL maintainer "The Infrastructure Company GmbH <info@servercow.de>"
 
 RUN apk add --update --no-cache \
 	curl \
@@ -18,6 +18,11 @@
 
 COPY docker-entrypoint.sh /docker-entrypoint.sh
 
+# healthcheck (nslookup)
+COPY healthcheck.sh /healthcheck.sh
+RUN chmod +x /healthcheck.sh
+HEALTHCHECK --interval=30s --timeout=10s CMD [ "/healthcheck.sh" ]
+
 ENTRYPOINT ["/docker-entrypoint.sh"]
 
 CMD ["/usr/sbin/unbound"]
diff --git a/mailcow/src/mailcow-dockerized/data/Dockerfiles/unbound/healthcheck.sh b/mailcow/src/mailcow-dockerized/data/Dockerfiles/unbound/healthcheck.sh
new file mode 100644
index 0000000..8c4508f
--- /dev/null
+++ b/mailcow/src/mailcow-dockerized/data/Dockerfiles/unbound/healthcheck.sh
@@ -0,0 +1,12 @@
+#!/bin/bash
+
+nslookup mailcow.email 127.0.0.1 1> /dev/null
+
+if [ $? == 0 ]; then
+    echo "DNS resolution is working!"
+    exit 0
+else
+    echo "DNS resolution is not working correctly..."
+    echo "Maybe check your outbound firewall, as it needs to resolve DNS over TCP AND UDP!"
+    exit 1
+fi